The value output by process.cwd() is different during build and run, causing the file to not be read

[mikeguo99]

I found many responses suggesting that when deploying on Vercel, files should be read using path.join(process.cwd(), "your.file.path"). This works fine locally and even worked previously on Vercel. However, today I discovered that deploying a new project on Vercel with this method results in an error:

Error: ENOENT: no such file or directory, open '/var/task/your/file/path' ...

I then added logs and observed that the output of process.cwd() differs between build and runtime, specifically:

• /vercel/path0 when building;
• /var/task when running.

I suspect that Vercel has modified the build output directory in a recent version, and now my source code's /data directory is not being copied to /var/task.

Therefore, I want to know if Vercel has an official solution to this issue.

[mikeguo99]

oh I solved it by specifying experimental.outputFileTracingIncludes to next.config.mjs. Like bellow:

const nextConfig = {
  experimental: {
    outputFileTracingIncludes: {
      "/": ["./data/**/*"],
    },
  },
};

export default nextConfig;

[JRH89]

worked for me.